Contrary to the claims made by countless "certified translators" who advertise on the web and the yellow pages, in the United States there is no such thing as a "certified translator," as there is no official certification program for translators in this country.   Next time someone claims to be a "certified translator," ask who certified him.

In the US, a certified translation is one where the translator has signed an oath before a notary public certifying the accuracy and correctness of the translation, as well as the fact that he is qualified to make such a certification.

Since in the US, there are no restrictions as to who can or cannot claim to be a translator, anyone willing to swear that he or she is qualified to translate into and from any  language pair can certify a translation.

What constitutes a dialect and what to do about it is one of the most misunderstood concepts in translation, perhaps second only to the "native speaker" syndrome (the pernicious idea, promoted by some language schools, that being a native speaker qualifies a person to translate).

Every major language has regional and class variations, but more importantly, every language also has clear standards and guidelines for correct and incorrect grammar and usage. 

Although there may be times when it is appropriate to write in a regional or class dialect (targeted advertising comes to mind), business communications (and this includes technical writings, contracts, legislation, financial statements, etc.) must always be written in standard language.

Being a native speaker of a foreign language does not make a person a translator, any more than being a native speaker of English makes a person a writer.  There are three reasons for this:

1. A person's knowledge of language is a function of their general and specialized education.  A person with a deficient education will have a deficient knowledge of language.

2. The native language, which is the first language learned by a person, may or may not be the person’s dominant language or language of primary competence.  Native speakers can have a grossly inadequate knowledge of their native language, particularly when they have been brought up and educated in a country where a language other than their native language is spoken. 

3. Even if the native speaker has a good education in his or her native language, that does not qualify a person to translate, as language competence  is only one of the prerequisites for translating competence.